How to calculate board feet
A board foot is a volume of wood 1 inch thick, 12 inches wide and 1 foot long — 144 cubic inches. To figure board feet of a board, multiply its three sizes and divide:
- Length in feet:
thickness (in) × width (in) × length (ft) ÷ 12 - Length in inches:
thickness (in) × width (in) × length (in) ÷ 144
Then multiply by the number of pieces. Example: ten 2×6 boards, 10 feet long — 2 × 6 × 10 ÷ 12 = 10 board feet each, 100 board feet for the stack. At $1.25 per board foot that is $125.
Nominal or actual size?
Board feet are figured on the nominal size. A planed 2×4 from the lumberyard is about 1½ × 3½ inches, but it is still sold as 2 × 4 = 5.33 board feet per 8-foot piece. Rough lumber off a sawmill is sawn to full size, so a rough 2×4 really is about 2 × 4 inches and the number is the true volume of the board.
Hardwood thickness in quarters
Hardwood is sold by quarters of an inch: 4/4 is 1 inch, 5/4 is 1¼, 6/4 is 1½, 8/4 is 2 inches. You can type the quarters straight into the calculator — 8/4 reads as 2. Hardwood usually comes in random widths: measure each board (or add the widths up and enter the sum) and use the actual length.
Price per board foot and MBF
Lumber and logs are priced per board foot or per thousand board feet — MBF. $900 per MBF is $0.90 per board foot. One cubic foot of wood holds 12 board feet, one cubic meter about 424.
Board feet chart for common lumber sizes
| Size (in × in × ft) | Board feet per piece | Pieces per 1,000 bd ft |
|---|---|---|
| 1×4×8 | 2.67 | 375 |
| 1×6×8 | 4 | 250 |
| 1×8×8 | 5.33 | 188 |
| 1×10×8 | 6.67 | 150 |
| 1×12×8 | 8 | 125 |
| 2×4×8 | 5.33 | 188 |
| 2×4×10 | 6.67 | 150 |
| 2×4×12 | 8 | 125 |
| 2×4×16 | 10.67 | 94 |
| 2×6×8 | 8 | 125 |
| 2×6×10 | 10 | 100 |
| 2×6×12 | 12 | 83 |
| 2×6×16 | 16 | 63 |
| 2×8×8 | 10.67 | 94 |
| 2×8×12 | 16 | 63 |
| 2×8×16 | 21.33 | 47 |
| 2×10×12 | 20 | 50 |
| 2×10×16 | 26.67 | 38 |
| 2×12×12 | 24 | 42 |
| 2×12×16 | 32 | 31 |
| 4×4×8 | 10.67 | 94 |
| 4×4×12 | 16 | 63 |
| 4×6×12 | 24 | 42 |
| 6×6×8 | 24 | 42 |
| 6×6×12 | 36 | 28 |
| 8×8×12 | 64 | 16 |
Boards per cubic metre for common metric sizes
Volume of one piece and how many pieces make one cubic metre, for rough sawn sizes in millimetres and lengths of 3, 4 and 6 metres.
| Size, mm | m³ each (6 m) | Pieces per m³ | ||
|---|---|---|---|---|
| 3 m | 4 m | 6 m | ||
| 25×100 | 0.0150 | 133.3 | 100.0 | 66.7 |
| 25×150 | 0.0225 | 88.9 | 66.7 | 44.4 |
| 25×200 | 0.0300 | 66.7 | 50.0 | 33.3 |
| 32×100 | 0.0192 | 104.2 | 78.1 | 52.1 |
| 32×150 | 0.0288 | 69.4 | 52.1 | 34.7 |
| 40×150 | 0.0360 | 55.6 | 41.7 | 27.8 |
| 50×100 | 0.0300 | 66.7 | 50.0 | 33.3 |
| 50×150 | 0.0450 | 44.4 | 33.3 | 22.2 |
| 50×200 | 0.0600 | 33.3 | 25.0 | 16.7 |
| 100×100 | 0.0600 | 33.3 | 25.0 | 16.7 |
| 100×150 | 0.0900 | 22.2 | 16.7 | 11.1 |
| 150×150 | 0.1350 | 14.8 | 11.1 | 7.4 |
| 200×200 | 0.2400 | 8.3 | 6.3 | 4.2 |
Questions sawyers ask
How many board feet are in a 2x4x8?
5.33 board feet: 2 × 4 × 8 ÷ 12. A 2x4x10 is 6.67, a 2x4x12 is 8.
How many board feet are in a 4x4x8?
10.67 board feet. A 6x6x8 timber is 24.
How many board feet will I get from a log?
That depends on the log rule your buyer uses and on how you saw it. Estimate the log with the log scale calculator (Doyle, Scribner, International ¼), then see what a real pattern yields in the log cutting calculator.